1. Field of the Invention
This invention relates in general to photocopying systems. In particular, this invention pertains to contact printers for transferring indicia from a drawing sheet to a sensitized sheet material. Still further, this invention relates to a vacuum contact printer for maintaining the drawing sheet and the sensitized sheet material in contiguous and adjacent relation to an upper surface of a vacuum chamber. More particularly, this invention pertains to a vacuum contact printer where the pressure drop loads caused by the vacuum chamber are distributed over a wide area of the drawing sheet and the sensitized sheet material in order to minimize any identations or other contour anomolies which may be present due to pressure drop force loadings on the sheets. Additionally, this invention relates to a vacuum contact printer minimizing distortions in the transfer of the indicia to the sensitized sheet material.
2. Prior Art
Contact printers for transferring indicia from a drawing sheet to a sensitized sheet material are known in the art. However, some of these prior art contact printers when utilizing vacuum chambers have caused indentations or other contour anomilies to exist in the drawing and sensitized sheets thereby causing unwanted and non-clear images to be transferred to the sensitized sheet material.
Additionally, in some prior contact printers the drawing sheet and sensitized sheets were moved relative to the light source thereby causing complexity in the various mechanisms associated with the contact printer. Still further, in other prior art vacuum contact printers, the mechanism for driving the light source through a predetermined distance was expensive to provide and costly in manufacturing.
Still further, in some other prior art printers the work face was not positioned in a face up location. This did not permit the user to position the work without movement of the work sheets.
In other prior art printers, the light source was substantially displaced from the sensitized material and resulted in possible halation effects which caused derrogatory transference of the indicia pattern.